[Asterisk-Users] rtp sound quality?

[Rich Adamson]

pstn -> sip gw -> * -> C7960

When I dial into * via the pstn, I hear the ivr menu just fine (good
quality). I press 3000 (valid extn), and I begin to hear ringing however the 
ring back is very very choppy.

I answer the C7960, and speech is clear in both directions. Place the C7960
extn on hold, and the MOH is very choppy. Checking 'sip show channels' indicates
both the sip gw and C7960 are using ulaw; Both are 100 meg on local LAN. Top
suggests all processes running less then 1 or 2 percent.

The choppy sound only happens on the sip gw (Mediatrix 1204). MOH between two
C7960's works fine. MOH via x100p works fine.

Tried canreinvite=no and yes; no difference. Using a packet sniffer, I see a
~200 millisecond delay about every 1/2 second or so (varys), but nothing within 
the trace to hint at a layer-2 problem.

Anyone have any thoughts as to why ringback and MOH are choppy but conversations
are fine?  Anything else I can look at to isolate the issue?

Rich